3, 6-bis (diloweralkylaminoanilino)-pyridazines



United States Patent 3,101,640 3,6-BIS(DILOWERALKYLAMINOANILINO)- PYRmAZlNES Douglas 1. Relyea, Pompton Plains, NJ., assignor to United States Rubber Company, New York, N.Y., a corporation of New Jersey No Drawing. Original application Oct. 29, 1962, Ser. No. 233,877. Divided and this application July 24, 1964, Ser. No. 385,055

2 Claims. (Cl. 260-450) This invention relates to new chemicals. The chemicals of the present invention are 3,6-disubstituted pyridazines represented by the formula wherein R and R are the same and are dialkylaminoanilino radicals. The alkyl groups in the dialkylarninoanilino radicals will generally have from 1 to 8 carbon atoms, e.g., methyl, ethyl, propyl, butyl, hexyl, octyl.

The chemicals of the present invention are prepared by reacting 3,6-dichloropyridazine, a known chemical, with the selected dialkylaminoaniline in an inert solvent, e.g., ethanol, xylene, toluene, benzene, pyridine, or dioxane.

The following examples illustrate the present invention.

Example 1 Preparation of 3,-6-pyridazinebis(4-dimethylaminoaniline), or 3,6-di(p-dimethylaminoanilino) pyridazine.

A solution of 136 gm. (1.0 mole) of redistilled p-dimethylaminoaniline in 250 ml. of reagent pyridine was treated with 74.5 gm. (0.50 mole) of 3,6dichloropyridazine. After approximately 20 minutes an exotherrn to 80 occurred. The mixture was then allowed to stand over the weekend at room temperature. The reaction mixture which had set to a semi solid mass was broken up and Washed thoroughly with water to remove the pyridine and pyridine hydrochloride. The residue was then dissolved in 500 ml. of water and 100 ml. of concentrated hydrochloric acid and the resultant dark brown solution filtered. The clear brown filtrate was run into 2.5 liters of water containing 80 gm. of sodium hydroxide and the dark yellow precipitate separated by filtration and dried at 50 C. and 50 mm. pressure. The product was recrystallized twice in 500 ml. of boiling o-dichlorobenzene, and filtered hot, resulting in 64 gm. of 3,-6-pyridazinebis(4-dimethylaminoaniline), a yellow crystalline material, plate-like in structure, and having a melting point of 234236 C.

Analysis for C H N Calculated Found Example 2 Rubber stock A was compounded on a two-roll mill by mixing into 100 parts of Hevea rubber, 2 parts of Patented Dec. 15, 1964 stearic acid, 45 parts of HAF (high abrasion furnace) carbon black, 3 parts of zinc oxide, 6 parts of Paraflux softener (a saturated polymerized petroleum hydrocarbon having a specific gravity of 1.02 and a Saybolt Furol viscosity of 250-350 seconds at 140 F.), 2.75 parts of sulfur, 0.75 part of N-cyclohexyl-Z-benzothiazolesulfenarnide accelerator, and 2 parts of 3,'6-pyridazinebis(4-dimethylaminoaniline). For comparison purposes, stock B was compounded similarly to stock A except there was incorporated in stock B a conventional commercial antioxidant combination, viz. 2.0 parts of BLE (a high temperature reaction product of diphenylamine and acetone having a specific gravity of 1.09) and 0.35 part of JZF (N,N'-diphenyl-p-phenylenediamine) instead of the 2 parts of 3,6-pyridazinebis(4-dimethylaminoaniline) Specimens of stocks A and B were cured in a press for 30, 45 and minutes at 293 F. and tested by the conventional testing methods used for rubber with results as shown in the following table:

Time Physical Properties of cure, A B

minutes Unaged:

Tensile Strength (p.s.i.) 30 3', 810 3, 860 45 3,610 3,910 90 3, 720 3, 510 Elongation at Break (Percent) 30 520 560 45 510 550 90 500 590 Modulus at 300% (p.s.l.)...- 30 1,750 1,500 45 1,700 1,475 90 1,450 1,200 Aged-48 hrs. in Air at 212 F.:

Tensile Strength (p.s.i.) 30 3,010 2, 590 45 2,890 2,520 90 2, 730 1,890 Elongation at Break (Percent) 30 39 340 45 380 360 90 400 340 Modulus at 300% (p.s.i.) 30 2,275 2, 275 45 2,300 2, 200 90 2,000 1, 850 Aged72 hrs. in Air at 212 F.:

Tensile Strength (p.s.i.) 30 2, 410 1,470 45 2,360 1,720 90 2,010 1,310 Elongation at Break (Percent) 30 380 250 45 340 270 00 310 250 Modulus at 300% (p.s.i.) 30 2,300 2,100 45 2,250 2,100 90 2,050 1,925 Aged-96 hrs. in 02 Bomb:

Tensile Strength (p.s.i.) 30 3,080 2, 940 45 2,810 2, 690 90 2,270 2,260 Elongation at Break (Percent) 30 420 440 45 390 410 90 400 400 Modulus at 300% (p.s.i 30 2,070 1,750 45 1,850 1,650 90 1,510 1,500 Aged-144 hrs. in 0, Bomb:

Tensile Strength (p.s.i.) 30 3,125 2,805 45 2,515 2,485 90 1,870 2,095 Elongation at Break (Percent) 30 450 440 45 410 420 1 t3 1) 28 li Moduusa 00 .s

1 Extrapolated values.

The results show that a rubber stock containing the chemical of the present invention ages in air and an oxygen atmosphere equally as well as a similar rubber stock containing the conventional commercial antioxidant combination as measured by such physical properties as 3 4 retention of tensile strength and degree of stiffness 1. A chemical represented by the formula (modulus rise). a

In view of the many changes and modifications that may be made without departing from the principles underlying the invention, reference should be made to the 5 appended claims for an understanding of the scope of the wherein R and are the Same and are i k l i P 9 affoffied P Y PE anilino radicals in which the alkyl groups have l to 8 This application is a dlVlSlOl'l of my application Serial carbon atoms N ber 2 files! ber 9, 1 962. 2. 3,6-pyridazinebis(4-dimethylarninoaniline).

Having thus described my invention, what I claim and 10 desire to protect by Letters Patent is: No references cited. 

1. A CHEMICAL REPRESENTED BY THE FORMULA 